paediatric vomiting

Question 1

5 week old boy brought for 2nd time in one week to A+E with persistent vomiting. parents say vomiting started 10 days earlier and that afer vomiting, he is always hungry. at the last visit, he was dx-ed as having GOR and started on feed thickeners and Gaviscon. until the age of 1 month, he was well and had been thriving. ABG performed and reported as follows:

pH 7.50 (normal range 7.35-7.45)
pCO2 5.0 kPa (normal range 4.6-6kPa)
p O2 12 kPa (normal range 10-13.5kPa)
Base deficit +5.8 (normal = 0)

(a) how would you assess his degree of hydration? list 5 indicators of dehydration

Answer 1

• mild-moderate
  
  • dry mucous membranes
  • reduced skin turgor (but sill visible for <2 secs)
  • increased CRT
  • sunken eyes
  • restlessness
  • thirsty / drinks easily
• severe
  
  • reduced level of consciousness
  • drinking poorly / not at all
  • reduced skin turgor (visible for >2 secs)
  • circulatory collapse (e.g. weak rapid pulse, cyanosis, reduced BP, increased RR, sunken anterior fontanelle)
• general
  
  • reduced body weight
  • reduced urine output
  • reduced tears

Question 2

(b) describe the abnormalities seen in the blood gas results

Answer 2

uncompensated metabolic alkalosis

Question 3

(c) describe in <50 words, how these changes arise

Answer 3

• vomiting causes loss of HCl
• excessive vomiting causes hypochloraemia
• hypochloraemia promotes bicarb resorption and reduces bicarb secretion in kidneys
• result is excess bicarbonate producing metabolic alkalosis

Question 4

(d) on more detailed examination, you notice gastric peristalsis and you feel a pyloric tumour in the upper abdomen.

what is the most appropriate next ix?

Answer 4

abdominal US

Question 5

(e) what is the most likely dx?

Answer 5

pyloric stenosis

Question 6

(f) what would be the operative procedure of choice?

Answer 6

pyloromyotomy